The main impediment to the commercialization of genetically modified (GM) fish is the incomplete assessment of food safety and the ecological impacts. The ecological impacts encompass global issues concerning gene flow and the escape of transgenic fish, which may pose a threat to wild natural fish stocks. Infertility control may be a core technology to solve the potential problem of GM fish release into the natural environment. The traditional approach to infertility control in GM fish is polyploidy technology. This technology causes infertility by changing the number of chromosomes in an individual. Temperature-shock or pressure-stress treatment of freshly fertilized fish eggs to induce triploidy is another common practice for infertility, but unfortunately triploid infertility is rarely 100% effective. An alternative method to induce infertility in fish is the blockade of gonadotropin releasing hormone (GnRH) expression by antisense RNA, ribozymes, or siRNA. However, although undeveloped or deficient gonads result from a knockdown of GnRH, the presence of antisense GnRH in fish do not result in 100% infertility. Furthermore, even if such a treatment was successful in achieving 100% infertility, the transgenic stocks with superior characteristics are not heritable. For this reason, infertility would need to be inducible; otherwise this infertility would be equivalent to ‘killing the goose that lays the golden eggs’.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies, especially in connection with establishing a platform technology for inducible infertility in GM fish.